The present invention relates to a liquid detergent composition or, more particularly, to a liquid detergent composition comprising a halogenated hydrocarbon solvent as the principal component suitable for cleaning the surface of various articles stained with oily, greasy or resinous contaminants.
Needless to say, several shaped articles of plastics are required to have extremely high cleanness on the surface in view of their use including, for example, plastic-made eye glasses and lenses in various optical instruments usually shaped by the method of casting polymerization of polycarbonate resins, poly(methyl methacrylate) resins, diethyleneglycol bisallylcarbonate resins and the like transparent plastics. These plastic-made articles as shaped are usually not free from contamination or stain on the surface, for example, with smears or fragment pieces of the plastic or perspiration and other excretions from the skin of the workers as in fingerprints as well as dirty matters coming from the working gloves. Accordingly, it is usual that the surfaces of these plastic articles are thoroughly cleaned using a detergent composition before they are packaged and shipped as commercial products.
In addition, although the requirement for the surface cleanness is not so rigorous as in the above mentioned plastic articles for optical uses, it is of course desirable for any articles shaped with the above mentioned resins that the surface should be fairly clean from the standpoint of commercial value of these transparent plastic articles while it is a rather difficult problem because the metal or glass molds used for the casting polymerization of these resins usually cannot be clean enough so that the plastic articles shaped with such an unclean mold are also not acceptable in respect of the surface cleanness. Therefore, it is essential that the metal or glass mold used for the casting polymerization of the above mentioned resins is thoroughly cleaned using a detergent composition after each time of the casting polymerization runs to prepare for the next use to be freed from any contaminants and dirty matters including plastic debris or fragment, greases, fingerprints and the like.
As a consequence of the nature of the stain or contaminant on the surface of the above mentioned plastic articles or molds used for the preparation thereof, which is usually oily, greasy or resinous, it is a common practice that an organic solvent is used as a detergent for the cleaning works in the above mentioned cases. For example, various kinds of halogenated hydrocarbon solvents, such as methylene chloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene and the like, are widely used for the purpose by virtue of their high detergent power along with the non-inflammability. Methylene chloride is particularly preferred due to its relatively low toxicity to the human body. These organic solvents, however, are not quite powerful as a detergent for the cleaning works in the above mentioned cases so that complete cleaning is hardly possible even by a prolonged washing with the solvent. Therefore, it is a usual practice that cleaning of the stain or contaminant with these halogenated hydrocarbon solvents is followed by manual wiping works of the surface with a cloth wet with acetone, alcohol or other solvent resulting in a great decrease in the productivity of the overall production process.
Accordingly, it is eagerly desired to develop a detergent composition with which a high efficiency is obtained in the cleaning works of the plastic-made articles and the molds for the preparation thereof.